Traditionally the primary technique adopted for stemming blood flow is the application of continuous pressure to the wound e.g. external wounds on body surface or dental wounds. This enables clotting factors to collect at the wound site and form a congealed blood mass to stem blood flow. However, this technique is not suitable for severe wounds and wounds having multiple bleeding points. Therefore, bleeding from the external wounds on body surface continues to be a major cause of death.
Death caused by bleeding out is a particular problem on the battle field. Typically wounds arising in this situation are accompanied by significant bleeding, and may result in death amongst the civilian population following trauma.
Several advancements have been made in the area of wound care in last few decades, however pre-hospital wound care and continuous wound care are stilled undeserved globally. Bleeding to death from traumatic injury is common in civilian and battle fields, which may or may not be accompanied with burns and other wounds that could be acute in nature.
Accident and trauma related injuries account for approximately 10% of deaths per year. Uncontrolled bleeding from wound site is a major cause of these preventable deaths. From a fatal wound approximately 40 ml/min of blood is lost and if it continues for 20 minutes, the victim dies of hemorrhagic shock. Bleeding to death before reaching medical facility is common to battle field injuries as well. Very often victims bleed to death due to lack of pre-hospital care, time and distance to reach a medical facility. Due to absence of external hemostatic products, the primary intervention to stop bleeding still remains to be cotton gauze using pressure. Lack of adequate pre-hospital care is stated as one of the prominent reasons of trauma related deaths.
Transportation of burn victims to the nearest medical facility is also a major unsolved issue. Due to this victim die of post injury infections which are preventable deaths. Though there is an unmet need in both the cases, it is pertinent to note that there is not even a single product which can stop bleeding quickly or to protect wounds until the victim reaches a medical facility.
At present the related products present in market are not made to address all these issues, but they have limited success to solve specific problems. The related products a product sold under the brand name QuickClot®. QuickClot® comprises a zeolite compound which absorbs water from blood flowing from a wound such that the clotting factors present in the blood become concentrated and the blood coagulates more quickly thereby the zeolite and the coagulated blood together form a coagulum to stem blood flow. After application of QuickClot® to the wound, zeolite absorbs water and QuickClot® generates heat, which reaches the temperature of 50° C. As it is necessary to apply constant pressure to the wound site following application of QuickClot® such temperatures make the application of pressure very difficult with medics needing to separate themselves from the wound site with any available material to prevent the discomfort accompanied with the heat generation. Furthermore, as the medic reaches for material to put between himself and the hot wound area he has to release the pressure. This can lead to channels appearing in the developing coagulum through which the blood can escape. If this happens then it is necessary to remove QuickClot® and start again. Ideally, a second person is required to ensure constant compression is applied. Other problems associated with QuickClot® also relate to heat generated upon contact with water. For example, as the product is a powder inevitably some settles on the skin surrounding the wound. If the skin is wet and heat generated can cause burns. Using QuickClot® in wet and windy weather is also problematic as it may cause discomfort or even burns to a person standing nearby.
Further during and after conventional dental procedures, e.g.; endodontic surgery, periodontal surgery, orthodontic treatment, tooth extractions, bleeding and fluid seepage typically occurs. Bleeding, fluid seepage or weeping, or other forms of fluid loss can also occur in the oral cavity as a result of injury or trauma to oral-maxillary tissue. Swelling and residual bleeding can be typically expected to persist during the healing period following the surgical procedure or injury. During the healing period, gum tissue regeneration occurs in the extraction sockets. It is thereby desirable during the healing period to take steps to stanch, seal, and/or stabilize the site of surgical intervention or the site of tissue injury or trauma against fluid loss due to bleeding, fluid seepage or weeping. During and after dental procedures or injury to the oral cavity, there is a need for quick and effective hemostasis.
Conventionally, absorbent cotton packs which are rolled or folded in the form of gauze pads are commonly used to stop the bleeding precipitated during and after dental procedures. While presence of such materials may absorb blood and body fluids which do not promote or create conditions conducive for rapid and long term hemostasis or healing.
Further products for control of bleedings from external wounds and dental wounds is described in U.S. Pat. No. 7,482,503 that comprises chitosan. The product is a sheet dressing comprising a chitosan layer. The dressing is applied to the site of the wound and forms a seal. The chitosan causes the blood to coagulate which together with the seal formed by the sheets stems the blood flow. However, such products must be applied directly to the source of bleeding i.e to an artery. Such application requires skill and accuracy. Military medics and first responders do not have the necessary skills to identify the source of bleeding and apply the dressing thereto. In any event, it would be extreme difficult to perform such a delicate operation on a battle field or at the trauma site.
GB2095995 discloses the use of pure chitosan acetate as a hemostatic material. However, the gel which forms from the pure salt is very thin as only the outermost surface of the material is available to act in a short period of time. Quite often this material fails to stop bleeding and even when it does, the clot is very thin and weak so that when the patient is moved, the clot compromised and bleeding resumes.
U.S. Pat. No. 7,371,403 relates to a wound dressing comprising a composite sponge comprising a freeze-dried and heat-compressed structure comprising chitosan biomaterial that stanches the blood flow at the wound site. The application of the heat may destroy the integrity of structure of biomaterial, which further fails to address the issue of batch to batch variability of chitosan that affects the end product, which is a major problem associated with natural polymers.
U.S. Pat. No. 7,981,872 relates to the hemostatic powder comprising a chitosan salt together with at least one medical surfactant.
US Patent Publication No. 20070237811 A1 describe a composition in which chitosan is prepared in a foamed gel that may be layered onto a suitable backing for use as a wound dressing, or the gel may be directly applied to wound, to affect hemostatic activity as a result of the chitosan.
U.S. Pat. No. 8,722,081 relates to hemostatic textile material to stop bleeding comprising: dialdehyde cellulose carrier, a selected component that prevents hemolysis; said component selected from the group consisting of tranexamic acid, and c-aminocaproic acid chemically immobilized thereon; and blood coagulation factor selected from the group consisting of chitosan and gelatin.
Therefore, it is an object of the invention to provide a hemostatic material which quickly stems the flow of blood from a wound and which is easy and safe to use.
According to the present invention there is provided a hemostatic material (scaffolds) comprising chitosan, tranexamic acid and an inorganic salt.
Advantageously, the hemostatic scaffold of the present invention can be applied by a person with only basic training. It is a matter of simply applying the scaffold to the wound area followed by pressure.